Can Vitamin D Prevent the Flu?

The facts about the power of Vitamin D

Claim: “The One Vitamin that Will Stop Flu in Its Tracks,” proclaims drmercola.com.

What’s in it: Vitamin D.

Cost: About $1.50 a month for 1,000 IU a day.

The facts: Vitamin D increases the production of antimicrobial peptides (small protein-like natural antibiotics) in the body’s cells. And in two U.S. studies, people with higher vitamin D levels in their blood had a lower risk of upper respiratory infections. Does that mean that taking vitamin D can stop the flu (or a cold)?

Japanese researchers gave 334 children either 1,200 IU of vitamin D or a placebo every day from December through March. The vitamin D takers had six cases of the flu for every ten cases in the placebo takers.

But three trials in adults — using 400 IU a day for six months, 800 IU a day for 11 to 25 months, or 2,000 IU a day for three months — all came up empty. In none of the studies did those taking vitamin D have fewer cases of the flu or other respiratory infections than similar people who were given a placebo.

Bottom line: The evidence that vitamin D can prevent colds or the flu is meager.

Are you a Nutrition Action Healthletter Subscriber?

Click the link below to be a member of our Nutrition Action Reader Panel and help give us insight to what you like best about each issue.

Notice: Content at this site is not intended to provide medical advice, which should be obtained from a qualified health professional. Any products evaluated or sources cited may contain information that is now outdated. Readers should check product labels to ensure any nutrient content has not changed since our review and still meets the criteria established by NutritionAction.com.